1. Field of the Invention
Embodiments of the present invention generally relate to a method and apparatus for a Doppler estimation algorithm for Orthogonal Frequency-Division Multiplexing (OFDM).
2. Description of the Related Art
The DTV2000 chip is intended to be a high-performance DVB-H receiver. As such, it is capable of receiving video reliably in a highly mobile environment. The mobility introduces channel fading that disrupts the orthogonally of the Orthogonal Frequency-Division Multiplexing (OFDM) carriers (or tones) in the DVB-H signal. An inter-carrier interference (ICI) cancellation algorithm included in the receiver enables reliable performance in these challenging conditions. The ICI canceller compensates for the interference between neighboring OFDM carriers by subtracting estimates of the ICI from neighboring tones before equalization via the traditional single-tap frequency domain equalizer (FEQ).
The ICI cancellation algorithm improves receiver performance when the channel has a high Doppler spread. In channels with low Doppler spreads, the cancellation algorithm degrades performance. At such low Doppler frequencies, the ICI estimates are below the noise floor and may be noise-dominated. When fed corrupt ICI estimates, the ICI cancellation algorithm degrades receiver performance.
Therefore, there is a need for an improved method and apparatus for a Doppler estimation algorithm for OFDM.